Garlic isn’t just for keeping vampires away. Pungent garlic also controls garden pests in at least three proven ways, according to several leading garden experts and authors.

Companion planting with garlic

You may not want a companion with garlic breath, but plenty of plants are happy with garlic as a companion. The pungent smell keeps insects from finding the sweet-smell of roses, peaches and more. Cornell Cooperative Extension experts note that pest deterrence through companion planting is difficult to prove, but said there is substantial anecdotal evidence of success.

In his Giant Book of Garden Solutions, plant expert Jerry Baker recommends planting garlic in rose beds to ward off cane borers, aphids, rose chafers and Japanese beetles. To repel peach tree borers, Baker recommends planting a ring of garlic around a peach tree trunk, but the garlic and the tree must be planted at the same time.

In The Garden Pests and Diseases Specialist, David Squire suggests planting garlic around carrots to mask the carrot smell and keep carrot flies away. Leeks and onions also help.

Garlic can also help in other ways. The North Carolina experts suggest companion plantings of garlic can improve the growth and flavor of beets, cabbage and peas. On the other hand, they warn that garlic can inhibit the growth of beans if planted too close.

Garlic pesticides

Garlic also forms the basis of effective, organic pesticides to spray on plants and ward off bugs. Garlic is often used in conjunction with hot peppers as a natural pesticide double whammy. Such bug sprays are commercially available or can be homemade.

Studies have shown success with garlic pesticides, both for mosquito larvae and many garden pests. However, much like companion planting, most evidence regarding garlic pesticides is anecdotal. Garlic-based pesticides can kill off some bugs, but are typically most effective as a preventive measure. Use before bugs appear on crops that have fallen victim to a certain bug in previous seasons.

Baker offers two recipes for repelling a wide variety of bugs throughout the garden. The first calls for pureeing three hot green peppers, three garlic cloves and one small onion. Then add one tablespoon of liquid dish soap and three cups of water. Let it steep for a day, then strain with a cheesecloth.

His second recipe is a puree of four cloves of garlic, one small onion, one small jalapeno pepper, steeped in a quart of water for two hours, then strained and mixed with one teaspoon of Murphy’s Oil Soap and one teaspoon of vegetable oil.

Either mixture can be mist sprayed onto plants, coating the tops and bottoms of leaves.

To specifically target vegetables, Baker suggests mixing six cloves of crushed garlic, one small onion, one tablespoon each of cayenne pepper and liquid dish soap with one quart of warm water. Strain and mist onto vegetable leaves, covering both sides.

For some more specialized mixtures, Baker suggests making a cup of garlic oil and keeping it in the fridge. Mince one garlic bulb into a cup of vegetable oil, then let the tincture steep in the fridge for a couple of days. “If the aroma is so strong that you take a step back, you’re ready to roll,” he writes. Otherwise add another half bulb of garlic and wait another day. Filter the pungent oil into another jar and use in a variety of garlic pesticides.

To control aphids, Baker recommends diluting one tablespoon of garlic oil with three drops of liquid dish soap in one quart of water. Use a mist sprayer to keep aphids off plants.

To prevent and get rid of potato beetles, cabbage moths and cabbage loopers, Baker suggests boiling one clove of garlic in one cup of water, along with four cloves and a handful of wild mustard leaves. Let the “tea” cool, then mist spray onto potato and cabbage leaves.

Fern Marshall Bradley offers several warnings regarding garlic sprays in her book, Rodale’s Vegetable Garden Problem Solver. First, a safety tip: wear gloves and avoid getting concentrated garlic juice on skin or eyes, as it can be a serious irritant.

Several scientific studies also suggest garlic has proven success in fighting off nasty fungal diseases. A 2008 report in the European Journal of Plant Pathology found garlic effective against tomato leaf blight and tuber blight. Baker, dubbed “America’s Master Gardener,” writes that “there’s nothin’ fungi hate more than garlic.”

Baker suggests boiling four bulbs of crushed garlic and a half cup baking soda in one gallon of water. Then cool to room temperature, strain into a watering can and slowly soak the ground around the infected plants so the water soaks in really deeply. Dump out the crushed garlic and slowly work it into the soil.